This invention relates to a method and system for preheating particulate material and, more particularly, to an improved method and apparatus for preheating particulate material.
The present invention is applicable generally to a process for preheating particulate material, and in particular to a process for preheating and precalcining limestone by flowing the limestone and the hot kiln gases from the calcining kiln in countercurrent heat exchange relationship to each other. A preheating apparatus of this general type is known.
In the conventional prior art apparatus and system for preheating, precalcining and calcining limestone, the limestone is supplied to an overhead storage bin and directed downwardly through a basically annular preheating and precalcining passage to a central discharge through which it passes to a calcining kiln. Hot kiln off gases flow in countercurrent heat exchange relation through at least the lower region of the annular preheating and precalcining passage before exhausting from the preheating apparatus.
It is known that the dust particles in preheated limestone are laden with sulfur and other impurities. It would be beneficial, therefore, and it is an object of the present invention, to have a system and a method for removing such dust laden particles from particulate limestone before the limestone enters the kiln.